Measurement apparatus and measurement method

ABSTRACT

An EVM measurement value is appropriately determined while CPE/ICI correction is taken into account. In a measurement apparatus ( 300 ), an EVM measurer ( 305 ) measures a modulation quality of a signal transmitted from a transmission apparatus. An EVM determiner ( 306 ) determines whether or not the measurement value of the modulation quality is equal to or less than a first requirement value, in a case where correction relating to a phase noise of the transmission apparatus is necessary in a reception apparatus. The first requirement value herein is higher than a second requirement value used in the determination of the measurement value in a case where the correction relating to the phase noise of the transmission apparatus is unnecessary in the reception apparatus.

TECHNICAL FIELD

The present disclosure relates to a measurement apparatus and ameasurement method.

BACKGROUND ART

A communication system so called the fifth generation mobilecommunication system (5G) has been under study. In 5G, studies have beenconducted on flexibly providing functions respectively for use caseswhere communication traffic increases, where the number of terminals tobe connected increases, and where high reliability and/or low latency isrequired. There are three representative use cases, which are enhancedMobile Broadband (eMBB), massive Machine Type Communications (mMTC), andUltra Reliable and Low Latency Communications (URLLC). The 3rdGeneration Partnership Project (3GPP), which is an internationalstandardization organization, has been conducting studies on furtherevolution of the communication system from both aspects of furtherevolution of the LTE systems and New Radio Access Technology (RAT) (see,e.g., Non-Patent Literature (hereinafter, referred to as “NPL”) 1).

CITATION LIST Non-Patent Literature

-   NPL 1-   RP-161596, “Revision of SI: Study on New Radio Access Technology,”    NTT DOCOMO, September 2016-   NPL 2-   R1-1612335, “On phase noise effects,” Ericsson, November 2016-   NPL 3-   3GPP TS 36.101 V14.3.0, “User Equipment (UE) radio transmission and    reception (Release 14),” March 2017-   NPL 4-   3GPP TS 36.104 V14.3.0, “Base station (BS) radio transmission and    reception (Release 14),” March 2017

SUMMARY OF INVENTION

In New RAT, a signal of a high frequency of at least 6 GHz, for example,is used as a carrier wave compared with LTE/LTE Advanced. In particular,when a high frequency band and also a high modulation order (high-ordermodulation) are used, error rate characteristics degrade due to a CommonPhase Error (CPE) or Inter-carrier Interference (ICI) caused by a phasenoise of a local oscillator of a transmission apparatus (e.g., see NPL2). In this respect, studies have been carried out on performing CPEcorrection, using a Phase Tracking Reference Signal (PT-RS) or ICIcorrection (hereinafter, referred to as “CPE/ICI correction”), inaddition to performing channel equalization in a reception apparatus inNew RAT.

There is, however, a problem in that, when an Error Vector Magnitude(EVM) (modulation quality) measurement value of a transmission apparatusis determined, the CPE/ICI correction to be performed in a receptionapparatus is not taken into account under the test standards (e.g., seeNPLs 3 and 4) of a base station (BS), which may be called an “eNB,” anda mobile station (may be called a “terminal” or a “User Equipment (UE))”in LTE/LTE Advanced.

One non-limiting and exemplary embodiment of this disclosure facilitatesproviding a measurement apparatus and a measurement method each capableof appropriately determining an EVM measurement value, taking CPE/ICIcorrection into account.

A measurement apparatus according to an aspect of the present disclosureincludes: measurement circuitry, which, in operation, measures amodulation quality of a signal transmitted from a transmissionapparatus; and determination circuitry, which, in operation, determineswhether or not a measurement value of the modulation quality is equal toor less than a first requirement value, in a case where correctionrelating to a phase noise of the transmission apparatus is necessary ina reception apparatus, the first requirement value being higher than asecond requirement value used in the determination of the measurementvalue in a case where the correction relating to the phase noise of thetransmission apparatus is unnecessary in the reception apparatus.

A measurement apparatus according to an aspect of the present disclosureincludes: correction circuitry, which, in operation, performs correctionrelating to a phase noise for a signal transmitted from a transmissionapparatus; measurement circuitry, which, in operation, measures amodulation quality of the signal after the correction relating to thephase noise; and determination circuitry, which, in operation,determines whether or not a measurement value of the modulation qualityis equal to or less than a requirement value.

A measurement method according to an aspect of the present disclosureincludes: measuring a modulation quality of a signal transmitted from atransmission apparatus; and determining whether or not a measurementvalue of the modulation quality is equal to or less than a firstrequirement value, in a case where correction relating to a phase noiseof the transmission apparatus is necessary in a reception apparatus, thefirst requirement value being higher than a second requirement valueused in the determining of the measurement value in a case where thecorrection relating to the phase noise of the transmission apparatus isunnecessary in the reception apparatus.

Note that the comprehensive or specific aspects mentioned above may beimplemented by a system, an apparatus, a method, an integrated circuit,a computer program or a recoding medium, or any combination of thesystem, the apparatus, the method, the integrated circuit, the computerprogram, and the recoding medium.

According to an aspect of this disclosure, an EVM measurement value canbe appropriately determined while CPE/ICI correction is taken intoaccount.

The specification and the drawings make it clear more advantages andeffects in an aspect of this disclosure. Such advantages and/or effectsare provided by the features disclosed in some embodiments as well asthe specification and the drawings, but all of them do not have to beprovided in order to obtain one or more identical features.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a resource mapping example for PT-RSsand a DMRS;

FIG. 2 is a block diagram illustrating a part of a configuration of ameasurement apparatus according to Operation Example 1 of Embodiment 1;

FIG. 3 is a block diagram illustrating a configuration of a transmissionapparatus according to Operation Example 1 of Embodiment 1;

FIG. 4 is a block diagram illustrating a configuration of a receptionapparatus according to Operation Example 1 of Embodiment 1;

FIG. 5 is a block diagram illustrating the configuration of themeasurement apparatus according to Operation Example 1 of Embodiment 1;

FIG. 6 is a table illustrating configuration examples of EVM requirementvalues according to Operation Example 1 of Embodiment 1;

FIG. 7 is a flowchart illustrating processing of the measurementapparatus according to Operation Example 1 of Embodiment 1;

FIG. 8 is a block diagram illustrating a configuration of a transmissionapparatus according to Operation Example 2 of Embodiment 1;

FIG. 9 is a block diagram illustrating a configuration of a receptionapparatus according to Operation Example 2 of Embodiment 1;

FIG. 10 is a block diagram illustrating a configuration of a measurementapparatus according to Operation Example 2 of Embodiment 1;

FIG. 11 is a table illustrating configuration examples of EVMrequirement values according to Operation Example 2 of Embodiment 1;

FIG. 12 is a block diagram illustrating a configuration of a measurementapparatus according to Operation Example 1 of Embodiment 2;

FIG. 13 is a block diagram illustrating a configuration of a measurementapparatus according to Operation Example 2 of Embodiment 2;

FIG. 14 is a block diagram illustrating a configuration of a measurementapparatus according to Operation Example 1 of Embodiment 3;

FIG. 15 is a table illustrating configuration examples of EVMrequirement values according to Operation Example 1 of Embodiment 3;

FIG. 16 is a block diagram illustrating a configuration of a measurementapparatus according to Operation Example 2 of Embodiment 3; and

FIG. 17 is a table illustrating configuration examples of EVMrequirement values according to Operation Example 2 of Embodiment 3.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a detailed description will be given of embodiments of thepresent disclosure with reference to the accompanying drawings.

The higher the frequency band to which a signal is assigned or thehigher the modulation order to be used for a signal, the larger theeffect of CPE/ICI on error rate characteristics is. In this respect, asdescribed above, studies have been conducted on performing CPE/ICIcorrection using a PT-RS, in addition to performing channel equalizationin a reception apparatus in a case where a high frequency band and/orhigh modulation order is used.

PT-RSs are mapped densely in the time domain compared with channelestimation reference signals (Demodulation Reference Signals (DMRSs)) inorder to track CPE/ICI that fluctuates randomly in terms of time. FIG. 1illustrates a resource mapping example for PT-RSs and a DMRS in aphysical resource block (PRB).

The mapping density of PT-RSs is assumed to be configured in the timedomain where PT-RSs are mapped, for example, for every symbol, one oftwo neighboring symbols, or one of four neighboring symbols. Althoughstudies have been conducted on configuring the mapping density of PT-RSsin the frequency domain, the mapping density of PT-RSs in the frequencydomain is assumed to be low compared with the mapping density of DMRSsused in channel estimation. This is because since the effect of thephase noise is substantially the same in every subcarrier, a PT-RSmapped to any one of subcarriers can be shared by multiple PRBs.

According to the agreements on PT-RSs in 3GPP, PT-RSs are used between abase station (BS, eNB, or gNB) and a mobile station (terminal or UE)which is indicated by a base station using higher-layer signaling (suchas radio resource control (RRC) signaling). Moreover, an assumption ismade that the mapping density of PT-RSs in the time domain and in thefrequency domain flexibly changes in accordance with a modulation orderor a bandwidth and/or the like used between the base station and themobile station.

Meanwhile, studies have been carried out on methods of determining themapping density of PT-RSs by mobile stations. One of the methods is toindicate the mapping density of PT-RSs by a PT-RS dedicated controlsignal from a base station (explicit indication). Another method is topreviously determine a correspondence between the mapping density ofPT-RSs and another parameter (such as modulation order or bandwidth) andto determine the mapping density of PT-RSs with reference to thecorrespondence with the other parameter indicated by downlink controlinformation (DCI) at the time of communication (implicit indication).Note that, there is a possibility that a method other than these methodsis used.

Furthermore, application of the same precoding as that for DMRS ports toPT-RSs has been discussed, and PT-RS is possibly defined as DMRS. TheDMRSs used as PT-RSs are more densely mapped in terms of time than otherDMRSs. Moreover, reference signals used in correcting CPE/ICI caused bythe phase noise may be called by a name different from “PT-RS.”

Moreover, use of a Cyclic Prefix-Orthogonal Frequency DivisionMultiplexing (CP-OFDM) scheme in downlink (direction from a base stationto a mobile station) is assumed in New Radio (NR). Meanwhile, studieshave been carried out on both the CP-OFDM scheme and a Discrete FourierTransform-Spread OFDM (DFT-S-OFDM) scheme in uplink (direction from amobile station to a base station), and an assumption made that theseschemes are used while being switched in accordance with communicationenvironments, for example.

In each embodiment of the present disclosure, a description will begiven of a method of appropriately determining an EVM of a transmissionapparatus while taking into account the CPE/ICI correction relating tothe phase noise of a transmission apparatus in a measurement apparatusthat measures an EVM for output of the transmission apparatus anddetermines whether or not the EVM satisfies a requirement of acommunication system.

Embodiment 1 [Summary of Communication System]

A communication system according to Embodiment 1 includes a transmissionapparatus and a reception apparatus. More specifically, the transmissionapparatus is a base station and the reception apparatus is a mobilestation in downlink. Meanwhile, the transmission apparatus is a mobilestation and the reception apparatus is a base station in uplink.

In the communication system according to Embodiment 1 includes ameasurement apparatus that tests the performance of the transmissionapparatus. The measurement apparatus, for example, measures an EVM ofthe transmission apparatus, and determines whether or not the EVMmeasurement value, which is the result of measurement, is equal to orless than a prescribed value (EVM requirement value), i.e., themeasurement apparatus determines (evaluates) whether or not the EVMmeasurement value satisfies the prescribed requirement.

Hereinafter, a configuration of a communication system using the CP-OFDMscheme will be described in Operation Example 1 of Embodiment 1, and aconfiguration of a communication system using the DFT-S-OFDM scheme willbe described in Operation Example 2 of Embodiment 1.

OPERATION EXAMPLE 1

FIG. 2 is a block diagram illustrating a part of a configuration ofmeasurement apparatus 300 according to Operation Example 1. Inmeasurement apparatus 300 illustrated in FIG. 2, EVM measurer 305measures a modulation quality (EVM) of a signal transmitted fromtransmission apparatus 100. In a case where correction (CPE/ICIcorrection) relating to the phase noise of transmission apparatus 100 isnecessary in reception apparatus 200, EVM determiner 306 determineswhether or not the measurement value of the modulation quality is equalto or less than a first requirement value (EVM requirement value (b) tobe described, hereinafter). The first requirement value herein is higherthan a second requirement value (EVM requirement value (a) to bedescribed, hereinafter) that is used in determining the measurementvalue in a case where the correction (CPE/ICI correction) relating tothe phase noise of transmission apparatus 100 is unnecessary inreception apparatus 200.

[Configuration of Transmission Apparatus]

FIG. 3 is a block diagram illustrating a configuration of transmissionapparatus 100 according to Operation Example 1 of Embodiment 1. In FIG.3, transmission apparatus 100 includes PT-RS generator 101, DMRSgenerator 102, mapping section 103, inverse fast Fourier transform(IFFT) section 104, CP adder 105, local oscillator 106, frequencyconverter 107, and antenna 108.

PT-RS generator 101 generates a PT-RS in a case where CPE/ICI correctionis considered necessary, and outputs the generated PT-RS to mappingsection 103. In a case where, for example, the frequency band to whichtransmission data is assigned is high (e.g., frequency band not lessthan a prescribed threshold) or the modulation order for thetransmission data is high (e.g., modulation order not less than aprescribed threshold), the effect of a phase noise of local oscillator106 and/or the like is assumed to be large (i.e., CPE/ICI correction isconsidered necessary). Thus, PT-RS generator 101 may generate a PT-RS inthis case.

DMRS generator 102 generates a DMRS and outputs the generated DMRS tomapping section 103.

Mapping section 103 maps, to a time and frequency domain resource (e.g.,PRB), the transmission data to be input, the PT-RS input from PT-RSgenerator 101 (when CPE/ICI correction is considered necessary), and theDMRS input from DMRS generator 102, and outputs the mapped signal toIFFT section 104.

IFFT section 104 applies IFFT processing to the signal input frommapping section 103 and outputs the signal obtained by the IFFTprocessing to CP adder 105.

CP adder 105 adds a CP to the signal input from IFFT section 104 andoutputs the signal to which the CP has been added (i.e., CP-OFDM signal)to frequency converter 107.

Local oscillator 106 generates a carrier signal for frequency conversionin frequency converter 107 and outputs the carrier signal to frequencyconverter 107.

Frequency converter 107 applies frequency conversion (up-conversion) tothe signal input from CP adder 105, using the carrier signal input fromlocal oscillator 106, and outputs the signal obtained by the frequencyconversion to antenna 108.

Antenna 108 radiates the signal input from frequency converter 107.

[Configuration of Reception Apparatus]

FIG. 4 is a block diagram illustrating a configuration of receptionapparatus 200 according to Operation Example 1 of Embodiment 1. In FIG.4, reception apparatus 200 includes CP remover 201, fast Fouriertransform (FFT) section 202, channel equalizer 203, PT-RS checker 204,CPE/ICI corrector 205, and symbol detector 206.

CP remover 201 removes a CP from the signal transmitted fromtransmission apparatus 100 and outputs the signal obtained by the CPremoval to FFT section 202.

FFT section 202 applies FFT processing to the signal input from CPremover 201 and outputs the signal obtained by the FFT processing tochannel equalizer 203.

Channel equalizer 203 applies channel equalization to the signal inputfrom FFT section 202 and outputs the signal obtained by the channelequalization to PT-RS checker 204.

PT-RS checker 204 checks whether or not use of a PT-RS is indicated forthe signal input from channel equalizer 203. In a case where use of aPT-RS is indicated, PT-RS checker 204 outputs the input signal toCPE/ICI corrector 205. Meanwhile, in a case where use of a PT-RS is notindicated, PT-RS checker 204 outputs the input signal to symbol detector206. Note that, whether or not a PT-RS is used may be indicatedexplicitly or implicitly by a control signal and/or the like.

CPE/ICI corrector 205 estimates the CPE/ICI of the input signal, using aPT-RS contained in the signal input from PT-RS checker 204, and corrects(performs CPE/ICI correction on) the input signal based on the result ofestimation. CPE/ICI corrector 205 outputs the corrected signal to symboldetector 206.

Symbol detector 206 detects a symbol from the signal received from PT-RSchecker 204 or CPE/ICI corrector 205 and outputs the received signal.

[Configuration of Measurement Apparatus]

FIG. 5 is a block diagram illustrating a configuration of measurementapparatus 300 according to Operation Example 1 of Embodiment 1.Measurement apparatus 300 illustrated in FIG. 5 measures an EVM of ameasurement-target transmission apparatus that transmits a CP-OFDMsignal (e.g., transmission apparatus 100 illustrated in FIG. 3).

In FIG. 5, measurement apparatus 300 includes time/frequencysynchronizer 301, CP remover 302, FFT section 303, channel equalizer304, EVM measurer 305, and EVM determiner 306.

Note that, CP remover 302, FFT section 303, and channel equalizer 304 inmeasurement apparatus 300 have configurations similar to those of CPremover 201, FFT section 202, and channel equalizer 203, respectively,in reception apparatus 200 illustrated in FIG. 4. Measurement apparatus300 assumes a point after the FFT processing and channel equalization(EVM measurement point) in reception apparatus 200 and measures an EVM.

Time/Frequency synchronizer 301 synchronizes the times and frequenciesof CP remover 302, FFT section 303, and channel equalizer 304.

CP remover 302 removes a CP from the signal transmitted frommeasurement-target transmission apparatus 100 and outputs the signalobtained by the CP removal to FFT section 303.

FFT section 303 applies FFT processing to the signal input from CPremover 302 and outputs the signal obtained by the FFT processing tochannel equalizer 304.

Channel equalizer 304 applies channel equalization to the signal inputfrom FFT section 303 and outputs the signal obtained by the channelequalization to EVM measurer 305.

EVM measurer 305 detects a symbol from the signal input from channelequalizer 304 in a manner similar to that of symbol detector 206 ofreception apparatus 200. EVM measurer 305 compares the detected symbolwith a known ideal symbol and measures (calculates) an EVM based on amagnitude of an error between the detected symbol and the ideal symbolon a complex plane. EVM measurer 305 outputs the EVM measurement valueto EVM determiner 306.

EVM determiner 306 determines whether or not the EVM measurement valueinput from EVM measurer 305 satisfies a prescribed requirement (whetheror not the EVM measurement value is equal to or less than the EVMrequirement value). More specifically, in a case where the EVMmeasurement value is equal to or less than the EVM requirement value,EVM determiner 306 determines that measurement-target transmissionapparatus 100 is a transmission apparatus usable in the communicationsystem. Meanwhile, in a case where the EVM measurement value exceeds theEVM requirement value, EVM determiner 306 determines thatmeasurement-target transmission apparatus 100 is a transmissionapparatus not usable (not satisfying the requirement) in thecommunication system.

[Operations of Measurement Apparatus 300]

Next, a detailed description will be given of operations of measurementapparatus 300.

As described above, in a case where a high frequency band or a highmodulation order is used for transmission data to be transmitted fromtransmission apparatus 100 (FIG. 3) to reception apparatus 200 (FIG. 4)(i.e., when the effect of a phase noise of transmission apparatus 100(local oscillator 106) and/or the like is large), transmission apparatus100 maps a PT-RS, and reception apparatus 200 performs CPE/ICIcorrection, using the PT-RS.

Although CPE/ICI is actually corrected in reception apparatus 200, anEVM is measured for a signal on which no CPE/ICI correction is applied(signal after channel equalization) in measurement apparatus 300.Meanwhile, the current test standard (e.g., see NPLs 3 and 4) does notassume CPE/ICI correction in EVM requirement values used in evaluationat the time of EVM measurement.

Accordingly, when the current test standard is applied in measurementapparatus 300, CPE/ICI correction is applied in reception apparatus 200to the signal transmitted from transmission apparatus 100, and the EVMis improved (reduced). In the test (EVM determination) of measurementapparatus 300, however, there is a possibility that transmissionapparatus 100 is not allowed because the improvement of the EVM inreception apparatus 200 is not taken into account, and the EVMmeasurement value exceeds the EVM requirement value. More specifically,there is a possibility that the performance of transmission apparatus100 is undervalued under the current test standard.

In this respect, in Embodiment 1, an EVM requirement value for an EVMmeasurement value of a case where the CPE/ICI correction relating to thephase noise of transmission apparatus 100 is necessary in receptionapparatus 200 is configured in addition to an EVM requirement value foran EVM measurement value of a case where the CPE/ICI correction relatingto the phase noise of transmission apparatus 100 is unnecessary inreception apparatus 200 (i.e., similar to the current test standard).More specifically, measurement apparatus 300 (EVM determiner 306) newlyconfigures an EVM requirement value assuming that the CPE/ICI correctionis performed in reception apparatus 200.

The lower the EVM requirement value is (i.e., the lower the required EVMvalue is), the higher the performance required in transmission apparatus100 is. In this respect, in Embodiment 1, the EVM requirement value ofthe case where the CPE/ICI correction is necessary in receptionapparatus 200 is configured to be higher than the EVM requirement valueof the case where the CPE/ICI correction is unnecessary in receptionapparatus 200 (i.e., the requirement is eased), while the improvement ofthe EVM in reception apparatus 200 is taken into account.

More specifically, when the CPE/ICI correction in reception apparatus200 is taken into account, measurement apparatus 300 measures an EVM ata point before the CPE/ICI correction is performed, as in the currenttest standard (LTE/LTE-Advanced standard), but a value higher than theEVM requirement value of the current test standard (i.e., non-strictrequirement value) is configured. More specifically, in a case where theCPE/ICI correction relating to the phase noise of transmission apparatus100 is necessary in reception apparatus 200, measurement apparatus 300determines whether or not the EVM measurement value is equal to or lessthan the EVM requirement value that is higher than the EVM requirementvalue used in determination of the EVM measurement value in a case wherethe CPE/ICI correction relating to the phase noise of transmissionapparatus 100 is unnecessary in reception apparatus 200.

Note that, in Embodiment 1, the frequency band and the modulation orderfor the signal transmitted from transmission apparatus 100 are used as atransmission parameter relating to the increase or decrease in theeffect of the phase noise of transmission apparatus 100. Morespecifically, in a case where a high frequency band or a high modulationorder is used, a standard is newly configured, in which the EVMrequirement value is eased (configured to be high) compared with a casewhere neither a high frequency band nor a high modulation order is used.

FIG. 6 illustrates examples of EVM requirement values of a case whereCPE/ICI correction is unnecessary (e.g., case where neither highfrequency band nor high modulation order is used) (a) (hereinafter,referred to as “EVM requirement values (a)”) and EVM requirement valuesof a case where CPE/ICI correction is necessary (e.g., case where highfrequency band and high modulation order are used) (b) (hereinafter,referred to as “EVM requirement values (b)”).

An assumption is made herein that, when an EVM measurement value oftransmission apparatus 100 using a high frequency band and a highmodulation order satisfies the EVM requirement value (b), the error ratecharacteristics are obtained which are equivalent to those of a casewhere the EVM requirement value (a) is satisfied in transmissionapparatus 100 that requires no CPE/ICI correction.

More specifically, in a case where QPSK (low modulation order)illustrated in FIG. 6 is used, the EVM requirement value (a) of the casewhere CPE/ICI correction is unnecessary and the EVM requirement value(b) of the case where CPE/ICI correction is necessary are the same.Meanwhile, in a case where 16QAM, 64QAM, and 256QAM (high modulationorders) illustrated in FIG. 6 are used, the EVM requirement values (b)of the case where CPE/ICI correction is necessary are configured to beeased values (high values) compared with the EVM requirement values (a)of the case where CPE/ICI correction is unnecessary. In FIG. 6, forexample, the higher the modulation order is, the higher the degree ofincrease in the EVM requirement values (b) with respect to the EVMrequirement values (a) is.

Note that, the configurations of the EVM requirement values illustratedin FIG. 6 are exemplary and are not limited to the values illustrated inFIG. 6. Moreover, although the correspondence between the modulationorders and EVM requirement values is illustrated in FIG. 6, acorrespondence between frequency bands and EVM requirement values may beconfigured in a similar manner. In a case where a high frequency band isused, for example, for any modulation scheme (modulation order) to beused, the EVM requirement values (b) of the case where CPE/ICIcorrection is necessary may be configured to be eased values (highvalues) compared with the EVM requirement values (a) of the case whereCPE/ICI correction is unnecessary (not illustrated).

Next, FIG. 7 illustrates an example of a processing flow of measurementapparatus 300.

In FIG. 7, measurement apparatus 300 (CP remover 302, FFT section 303,and/or channel equalizer 304) applies reception processing similar tothat of reception apparatus 200 to the signal (CP-OFDM signal)transmitted from measurement-target transmission apparatus 100 (ST 101).

Next, measurement apparatus 300 (EVM measurer 305) measures an EVM,using the received signal (ST 102).

Next, measurement apparatus 300 (EVM determiner 306) determines whetheror not CPE/ICI correction in reception apparatus 200 for the signaltransmitted from measurement-target transmission apparatus 100 isconsidered necessary (i.e., determines whether or not CPE/ICI correctionis present) (ST 103). EVM determiner 306, for example, may determinewhether or not CPE/ICI correction is present in reception apparatus 200based on a frequency band or a modulation order used for the signaltransmitted from measurement-target transmission apparatus 100. Notethat, information on the the frequency band or the modulation order usedin transmission apparatus 100 may be indicated explicitly or implicitlyusing a control signal and/or the like or may be prescribed at the timeof EVM measurement.

In a case where a high frequency band or a high modulation order isused, i.e., CPE/ICI correction in reception apparatus 200 is considerednecessary (ST 103: CPE/ICI correction is present), for example,measurement apparatus 300 (EVM determiner 306) performs EVMdetermination, using the EVM requirement value (b) of the case whereCPE/ICI correction is necessary illustrated in FIG. 6 (e.g., EVMrequirement value that is eased compared with the current test standard)(ST 104).

Meanwhile, in a case where a high frequency band or a high modulationorder is not used, i.e., CPE/ICI correction in reception apparatus 200is considered unnecessary (ST 103: No CPE/ICI correction), for example,measurement apparatus 300 (EVM determiner 306) performs EVMdetermination, using the EVM requirement value (a) of the case whereCPE/ICI correction is unnecessary illustrated in FIG. 6 (e.g., EVMrequirement value that similar to the current test standard) (ST 105).

As described above, measurement apparatus 300 determines whether or notCPE/ICI correction is present in reception apparatus 200 based on thefrequency band or the modulation order used for the signal transmittedfrom transmission apparatus 100 and switches between the EVM requirementvalues to be used for EVM determination based on the result ofdetermination.

Accordingly, measurement apparatus 300 can appropriately evaluate theEVM measurement value based on the frequency band or the modulationorder used for the signal transmitted from transmission apparatus 100(i.e., whether or not CPE/ICI correction in reception apparatus 200 isnecessary). More specifically, measurement apparatus 300 can perform EVMdetermination (EVM evaluation), taking into account the CPE/ICIcorrection (i.e., improvement of EVM) in reception apparatus 200 fortransmission apparatus 100 using a high frequency band or a highmodulation order. More specifically, measurement apparatus 300 can allowfor communication for transmission apparatus 100 having the phase noisenot allowed under the current test standard, using a test standard thattakes into account the improvement of an EVM by the CPE/ICI correctionin reception apparatus 200.

As described above, measurement-target transmission apparatus 100 usinga high frequency band or a high modulation order can performcommunication using the modulation scheme with reception apparatus 200provided with a CPE/ICI correction feature, in a case where arequirement by the EVM requirement value (b) of the case where CPE/ICIcorrection is necessary illustrated in FIG. 6 is satisfied in EVMdetermination by measurement apparatus 300.

Moreover, measurement-target transmission apparatus 100 can use localoscillator 106 which produces a phase noise that may not be allowedunder the current test standard, in the case where a high frequency bandand a high modulation order are used. Stated differently, transmissionapparatus 100 does not have to include a high performance localoscillator for suppressing production of the phase noise to an extentallowable under the current test standard even in the case where a highfrequency band and a high modulation order are used. Thus, an increasein configuration or costs of local oscillator 106 provided totransmission apparatus 100 can be prevented.

OPERATION EXAMPLE 2

[Configuration of Transmission Apparatus]

FIG. 8 is a block diagram illustrating a configuration of transmissionapparatus 400 according to Operation Example 2 of Embodiment 1. In FIG.8, transmission apparatus 100 includes a discrete Fourier transform(DFT) section 401, PT-RS generator 402, DMRS generator 403, mappingsection 404, IFFT section 405, local oscillator 406, frequency converter407, and antenna 408.

DFT section 401 applies DFT processing to the transmission data to beinput and outputs the transmission data obtained by the DFT processingto mapping section 404.

PT-RS generator 402 has a configuration similar to PT-RS generator 101(FIG. 3), generates a PT-RS in a case where CPE/ICI correction isconsidered necessary, and outputs the generated PT-RS to mapping section404.

DMRS generator 403 has a configuration similar to DMRS generator 102(FIG. 3), generates a DMRS, and outputs the generated DMRS to mappingsection 404.

Mapping section 404 maps the transmission data input from DFT section401, the PT-RS input from PT-RS generator 402 (when CPE/ICI correctionis necessary), and the DMRS input from DMRS generator 403 to a time andfrequency domain resource (e.g., PRB) and outputs the signal obtained bythe mapping to IFFT section 405.

IFFT section 405 applies IFFT processing to the signal input frommapping section 404 and outputs the signal obtained by the IFFTprocessing (i.e., DFT-S-OFDM signal) to frequency converter 407.

Local oscillator 406 generates a carrier signal for frequency conversionin frequency converter 407 and outputs the carrier signal to frequencyconverter 407.

Frequency converter 407 applies frequency conversion (up-conversion) tothe signal input from IFFT section 405, using the carrier signal inputfrom local oscillator 406, and outputs the signal obtained by thefrequency conversion to antenna 408.

Antenna 408 radiates the signal input from frequency converter 407.

[Configuration of Reception Apparatus]

FIG. 9 is a block diagram illustrating a configuration of receptionapparatus 500 according to Operation Example 2 of Embodiment 1. In FIG.9, reception apparatus 500 includes receiver 501, FFT section 502,channel equalizer 503, PT-RS checker 504, CPE/ICI corrector 505, andinverse discrete Fourier transform (IDFT) section 506.

Receiver 501 receives a signal (radio frequency (RF) signal) transmittedfrom transmission apparatus 400 and applies reception processing such asdown-conversion to the received signal. Receiver 501 outputs the signalobtained by the reception processing to FFT section 502.

FFT section 502 applies FFT processing to the signal input from receiver501 and outputs the signal obtained by the FFT processing to channelequalizer 503.

Channel equalizer 503 applies channel equalization to the signal inputfrom FFT section 502 and outputs the signal obtained by the channelequalization to PT-RS checker 504.

PT-RS checker 504 checks whether or not use of a PT-RS is indicated forthe signal input from channel equalizer 503 as in PT-RS checker 204(FIG. 4). In a case where use of a PT-RS is indicated, PT-RS checker 504outputs the input signal to CPE/ICI corrector 505. Meanwhile, in a casewhere use of a PT-RS is not indicated, PT-RS checker 504 outputs theinput signal to IDFT section 506. Note that, whether or not a PT-RS isused may be indicated explicitly or implicitly by a control signaland/or the like.

CPE/ICI corrector 505 estimates the CPE/ICI of the input signal, using aPT-RS contained in the signal input from PT-RS checker 504, and corrects(performs CPE/ICI correction on) the input signal based on the result ofestimation. CPE/ICI corrector 505 outputs the signal obtained by thecorrection to IDFT section 506.

IDFT section 506 applies IDFT processing to the signal input from PT-RSchecker 504 or CPE/ICI corrector 505 and outputs the signal obtained bythe IDFT processing (received signal).

[Configuration of Measurement Apparatus]

FIG. 10 is a block diagram illustrating a configuration of measurementapparatus 600 according to Operation Example 2 of Embodiment 1.Measurement apparatus 600 illustrated in FIG. 10 measures an EVM of ameasurement-target transmission apparatus that transmits a DFT-S-OFDMsignal (e.g., transmission apparatus 400 illustrated in FIG. 8).

In FIG. 10, measurement apparatus 600 includes receiver 601, FFT section602, channel equalizer 603, IDFT section 604, data EVM measurer 605,data EVM determiner 606, control-signal EVM measurer 607, andcontrol-signal EVM determiner 608.

Note that, receiver 601, FFT section 602, channel equalizer 603, andIDFT section 604 in measurement apparatus 600 have configurationssimilar to receiver 501, FFT section 502, channel equalizer 503, andIDFT section 506, respectively, in reception apparatus 500 illustratedin FIG. 9. Measurement apparatus 600 assumes a point after the FFTprocessing and channel equalization in reception apparatus 500 (EVMmeasurement point) and measures an EVM for a control signal (e.g.,Physical Uplink Control Channel (PUCCH) and/or the like) and/or areference signal (such as DMRS), and assumes a point after the IDFTprocessing in reception apparatus 500 (EVM measurement point) andmeasures an EVM for data (e.g., Physical Uplink Shared Channel (PUSCH)).

Receiver 601 receives a signal (RF signal) transmitted from ameasurement-target transmission apparatus (transmission apparatus 400)and applies reception processing such as down-conversion to the receivedsignal. Receiver 601 outputs the signal obtained by the receptionprocessing to FFT section 602.

FFT section 602 applies FFT processing to the signal input from receiver601 and outputs the signal obtained by the FFT processing to channelequalizer 603.

Channel equalizer 603 applies channel equalization to the signal inputfrom FFT section 602 and outputs the signal obtained by the channelequalization to IDFT section 604 and control-signal EVM measurer 607.

IDFT section 604 applies IDFT processing to the signal input fromchannel equalizer 603 and outputs the signal obtained by the IDFTprocessing to data EVM measurer 605.

Data EVM measurer 605 detects a data symbol from the signal input fromIDFT section 604. Data EVM measurer 605 compares the detected datasymbol with a known ideal symbol and measures (calculates) an EVM ofdata from a magnitude of an error between the detected data symbol andthe ideal symbol on a complex plane. Data EVM measurer 605 outputs anEVM measurement value to data EVM determiner 606.

Data EVM determiner 606 determines whether or not the EVM measurementvalue input from data EVM measurer 605 satisfies a prescribedrequirement (whether or not the EVM measurement value is equal to orless than the EVM requirement value).

Control-signal EVM measurer 607 detects a symbol of a control signal(control symbol) and/or a symbol of a reference signal (reference signalsymbol) from the signal input from channel equalizer 603. Control-signalEVM measurer 607 compares the detected control symbol and/or thereference signal symbol with a known ideal symbol and measures(calculates) an EVM of the control signal and/or the reference signalfrom a magnitude of an error between the control symbol and/or thereference signal symbol, and the ideal symbol on a complex plane.Control-signal EVM measurer 607 outputs the EVM measurement value tocontrol-signal EVM determiner 608.

Control-signal EVM determiner 608 determines whether or not the EVMmeasurement value input from control-signal EVM measurer 607 satisfies aprescribed requirement (whether or not the EVM measurement value isequal to or less than the EVM requirement value).

[Operations of Measurement Apparatus 600]

Next, a detailed description will be given of operations of measurementapparatus 600.

In Operation Example 2, as in Operation Example 1, an EVM requirementvalue for an EVM measurement value of a case where the CPE/ICIcorrection relating to the phase noise of transmission apparatus 400 isnecessary in reception apparatus 500 is configured, in addition to anEVM requirement value for an EVM measurement value of a case where theCPE/ICI correction relating to the phase noise of transmission apparatus400 is unnecessary in reception apparatus 500 (i.e., similar to thecurrent test standard). More specifically, measurement apparatus 600newly configures an EVM requirement value assuming that the CPE/ICIcorrection is performed in reception apparatus 500.

Note that, in Embodiment 1, as described above, the frequency band andthe modulation order for the signal transmitted from transmissionapparatus 400 are used as a transmission parameter relating to theincrease or decrease in the effect of the phase noise of transmissionapparatus 400. More specifically, in a case where a high frequency bandor a high modulation order is used, a standard is newly configured, inwhich the EVM requirement value is eased (configured to be high)compared with a case where neither a high frequency band nor a highmodulation order is used. Note that, information on the frequency bandor the modulation order used in transmission apparatus 400 may beindicated explicitly or implicitly using a control signal and/or thelike or may be prescribed at the time of EVM measurement.

FIG. 11 illustrates examples of EVM requirement values of a case whereCPE/ICI correction is unnecessary (e.g., case where neither highfrequency band nor high modulation order is used) (a) and EVMrequirement values of a case where CPE/ICI correction is necessary(e.g., case where high frequency band and high modulation order areused) (b).

An assumption is made herein that, when an EVM measurement value oftransmission apparatus 400 using a high frequency band and a highmodulation order satisfies the EVM requirement value (b), the error ratecharacteristics are obtained which are equivalent to those of a casewhere the EVM requirement value (a) is satisfied in transmissionapparatus 400 that requires no CPE/ICI correction.

More specifically, in a case where BPSK or QPSK (low modulation order)illustrated in FIG. 11 is used, the EVM requirement value (a) of thecase where CPE/ICI correction is unnecessary and the EVM requirementvalue (b) of the case where CPE/ICI correction is necessary are thesame. Meanwhile, in a case where 16QAM and 64QAM (high modulationorders) illustrated in FIG. 11 are used, the EVM requirement values (b)of the case where CPE/ICI correction is necessary are configured to beeased values (high values) compared with the EVM requirement values (a)of the case where CPE/ICI correction is unnecessary. In FIG. 11, forexample, the higher the modulation order is, the higher the degree ofincrease in the EVM requirement values (b) with respect to the EVMrequirement values (a) is.

Note that, the configurations of the EVM requirement values illustratedin FIG. 11 are exemplary and are not limited to the values illustratedin FIG. 11. Moreover, although the correspondence between the modulationorders and EVM requirement values is illustrated in FIG. 11, acorrespondence between frequency bands and EVM requirement values may beconfigured in a similar manner. In a case where a high frequency band isused, for example, for any modulation scheme (modulation order) to beused, the EVM requirement values (b) of the case where CPE/ICIcorrection is necessary may be configured to be eased values (highvalues) compared with the EVM requirement values (a) of the case whereCPE/ICI correction is unnecessary (not illustrated).

Measurement apparatus 600 (data EVM determiner 606 and control-signalEVM determiner 608) performs EVM determination using the EVM requirementvalue (b) of the case where the CPE/ICI correction is necessaryillustrated in FIG. 11 (e.g., an EVM requirement value that is easedcompared with the current test standard), for example, in a case where ahigh frequency band or a high modulation order is used, i.e., theCPE/ICI correction in reception apparatus 500 is considered necessary.Meanwhile, for example, in a case where a high frequency band or a highmodulation order is not used, i.e., the CPE/ICI correction in receptionapparatus 500 is considered unnecessary, measurement apparatus 600performs EVM determination, using the EVM requirement value (a) of thecase where the CPE/ICI correction is unnecessary illustrated in FIG. 11(e.g., EVM requirement value similar to the current test standard).

As described above, measurement apparatus 600 determines whether or notCPE/ICI correction is present in reception apparatus 500 based on thefrequency band or the modulation order used for the signal transmittedfrom transmission apparatus 400 and switches between the EVM requirementvalues to be used for EVM determination based on the result ofdetermination.

Accordingly, measurement apparatus 600 can appropriately evaluate theEVM measurement value based on the frequency band or the modulationorder used for the signal transmitted from transmission apparatus 400(i.e., whether or not CPE/ICI correction in reception apparatus 500 isnecessary) as in Operation Example 1. More specifically, measurementapparatus 600 can perform EVM determination, taking into account theCPE/ICI correction (i.e., improvement of EVM) in reception apparatus 500for transmission apparatus 400 using a high frequency band or a highmodulation order. More specifically, measurement apparatus 600 can allowfor communication for transmission apparatus 400 having the phase noisenot allowed under the current test standard, using a test standard thattakes into account the improvement of an EVM by the CPE/ICI correctionin reception apparatus 500.

As described above, measurement-target transmission apparatus 400 usinga high frequency band and a high modulation order can performcommunication using the modulation scheme with reception apparatus 500provided with a CPE/ICI correction feature, in a case where arequirement by the EVM requirement value (b) of the case where CPE/ICIcorrection is necessary illustrated in FIG. 11 is satisfied in EVMdetermination by measurement apparatus 600.

Moreover, measurement-target transmission apparatus 400 can use localoscillator 406 which produces a phase noise that may not be allowedunder the current test standard, in a case where a high frequency bandand a high modulation order are used. Stated differently, transmissionapparatus 400 does not have to include a high performance localoscillator for suppressing production of the phase noise to an extentallowable under the current test standard even in a case where a highfrequency band and a high modulation order are used. Thus, an increasein configuration or costs of local oscillator 406 provided totransmission apparatus 400 can be prevented.

Operation Examples 1 and 2 of Embodiment 1 have been described thus far.

As described above, in Embodiment 1, as with the current test standardin measurement apparatuses 300 and 600, an EVM having no effect ofCPE/ICE correction (EVM before CPE/ICI correction) is measured while anEVM requirement value taking into account the CPE/ICI correction inreception apparatuses 200 and 500 (i.e., new test standard) isconfigured. In a case where CPE/ICI correction is determined to benecessary for a signal transmitted from transmission apparatuses 100 and400, measurement apparatuses 300 and 600 perform EVM determination fortransmission apparatuses 100 and 400 based on the new test standard,respectively.

Thus, according to Embodiment 1, measurement apparatuses 300 and 600 caneach appropriately determine an EVM measurement value, taking intoaccount the CPE/ICI correction.

Moreover, according to Embodiment 1, switching between the EVMrequirement values in measurement apparatuses 300 and 600 according towhether or not the CPE/ICI correction in reception apparatuses 200 and500 is necessary allows transmission apparatuses 100 and 400 (basestation or mobile station) to include a local oscillator producing aphase noise that may not be allowed under the current test standard.More specifically, transmission apparatuses 100 and 400 (base station ormobile station) do not have to include a high performance localoscillator to be allowed under the current test standard.

Furthermore, measurement apparatuses 300 and 600 determine whether ornot the CPE/ICI correction is necessary, i.e., whether or not the newtest standard is applied in EVM determination based on a frequency bandor a modulation order used for a signal transmitted from transmissionapparatuses 100 and 400. Thus, measurement apparatuses 300 and 600 caneach appropriately perform EVM determination in both cases where theCPE/ICI correction is necessary and where the CPE/ICI correction isunnecessary.

Embodiment 2

In Embodiment 2, as in Embodiment 1, an EVM requirement value for an EVMmeasurement value of a case where the CPE/ICI correction relating to thephase noise of a transmission apparatus is necessary in a receptionapparatus is configured, in addition to an EVM requirement value for anEVM measurement value of a case where the CPE/ICI correction relating tothe phase noise of the transmission apparatus is unnecessary in thereception apparatus (i.e., similar to the current test standard) in EVMdetermination.

Hereinafter, a description will be given of a configuration of acommunication system using a CP-OFDM scheme in Operation Example 1 and aconfiguration of a communication system using a DFT-S-OFDM scheme inOperation Example 2, in a manner similar to Embodiment 1.

OPERATION EXAMPLE 1

Note that, a transmission apparatus and a reception apparatus accordingto Embodiment 2 include basic configurations common to transmissionapparatus 100 and reception apparatus 200 according to Embodiment 1, sothat a description will be given while FIGS. 3 and 4 are incorporatedherein.

[Configuration of Measurement Apparatus]

FIG. 12 is a block diagram illustrating a configuration of measurementapparatus 700 according to Operation Example 1 of Embodiment 2.Measurement apparatus 700 illustrated in FIG. 12 measures an EVM of ameasurement-target transmission apparatus that transmits a CP-OFDMsignal (e.g., transmission apparatus 100 illustrated in FIG. 3).

Note that, in FIG. 12, components that are similar to the components inEmbodiment 1 (FIG. 5) are assigned the same reference numerals and theirdescriptions are omitted. More specifically, measurement apparatus 700illustrated in FIG. 12 further includes CPE/ICI corrector 701 inaddition to the components that are similar to the components ofmeasurement apparatus 300 illustrated in FIG. 5.

CPE/ICI corrector 701 estimates the CPE/ICI of an input signal, using aPT-RS contained in the signal input from channel equalizer 304, andcorrects (performs CPE correction/ICI correction on) the input signalbased on the result of estimation as in reception apparatus 200 (CPE/ICIcorrector 205).

Note that, as in Embodiment 1, EVM measurer 305 measures an EVM, usingthe signal input from channel equalizer 304. More specifically, inEmbodiment 2, EVM measurer 305 assumes a point after FFT processing andchannel equalization but before CPE/ICI correction in receptionapparatus 200 (EVM measurement point) and measures an EVM.

EVM determiner 306 determines whether or not CPE/ICI correction ispresent in reception apparatus 200 and switches between the EVMrequirement values (e.g., see FIG. 6) to be used in EVM determination,based on the result of determination.

EVM determiner 306, for example, may check whether or not use of a PT-RSis indicated (i.e., whether or not a PT-RS is contained in a signal fromtransmission apparatus 100) and switch between the EVM requirementvalues to be used in EVM determination, in accordance with the result ofchecking as in reception apparatus 200 (PT-RS checker 204).Alternatively, EVM determiner 306 may switch between the EVM requirementvalues to be used in EVM determination, in accordance with atransmission parameter (such as frequency band or modulation order) usedfor a signal transmitted from transmission apparatus 100 as inEmbodiment 1. Note that, information indicating whether or not a PT-RSis used or information on the frequency band or the modulation order tobe used for the signal may be indicated explicitly or implicitly using acontrol signal and/or the like.

Alternatively, in Embodiment 2, measurement apparatus 700 (measurementapparatus having a CPE/ICI correction feature) may perform EVMdetermination for transmission apparatus 100 that requires CPE/ICIcorrection, and measurement apparatus 300 (measurement apparatus havingno CPE/ICI correction feature) described in Embodiment 1 may perform EVMdetermination for transmission apparatus 100 that requires no CPE/ICIcorrection.

As described above, measurement apparatus 700 switches between EVMrequirement values to be used in EVM determination, in accordance withnecessity of CPE/ICI correction (whether or not CPE/ICI correction ispresent).

Accordingly, measurement apparatus 700 can appropriately evaluate an EVMmeasurement value according to whether or not CPE/ICI correction isconsidered necessary. More specifically, measurement apparatus 700 canperform EVM determination, taking into account the CPE/ICI correction(i.e., improvement of EVM) in reception apparatus 200 for transmissionapparatus 100 for which CPE/ICI correction is considered necessary. Morespecifically, measurement apparatus 700 can allow for communication fortransmission apparatus 100 having the phase noise not allowed under thecurrent test standard, using a test standard that takes into account theimprovement of an EVM by the CPE/ICI correction in reception apparatus200.

As described above, measurement-target transmission apparatus 100 forwhich the CPE/ICI correction is considered necessary can performcommunication using the modulation scheme with reception apparatus 200provided with a CPE/ICI correction feature, in a case where arequirement by the EVM requirement value (b) of the case where CPE/ICIcorrection is necessary illustrated in FIG. 6 is satisfied in EVMdetermination by measurement apparatus 700.

Moreover, measurement-target transmission apparatus 100 can use localoscillator 106 which produces a phase noise that may not be allowedunder the current test standard in the case where the CPE/ICI correctionis considered necessary. Stated differently, transmission apparatus 100does not have to include a high performance local oscillator forsuppressing production of the phase noise to an extent allowable underthe current test standard even in the case where the CPE/ICI correctionis considered necessary. Thus, an increase in configuration or costs oflocal oscillator 106 provided to transmission apparatus 100 can beprevented.

OPERATION EXAMPLE 2

Note that, a transmission apparatus and a reception apparatus accordingto Embodiment 2 include basic configurations common to transmissionapparatus 400 and reception apparatus 500 according to Embodiment 1, sothat a description will be given while FIGS. 8 and 9 are incorporatedherein.

[Configuration of Measurement Apparatus]

FIG. 13 is a block diagram illustrating a configuration of measurementapparatus 800 according to Operation Example 2 of Embodiment 2.Measurement apparatus 800 illustrated in FIG. 13 measures an EVM of ameasurement-target transmission apparatus that transmits a DFT-S-OFDMsignal (e.g., transmission apparatus 400 illustrated in FIG. 8).

Note that, in FIG. 13, components that are similar to the components inEmbodiment 1 (FIG. 10) are assigned the same reference numerals andtheir descriptions are omitted. More specifically, measurement apparatus800 illustrated in FIG. 13 further includes CPE/ICI corrector 801 inaddition to the components that are similar to the components ofmeasurement apparatus 600 illustrated in FIG. 10.

CPE/ICI corrector 801 estimates the CPE/ICI of an input signal, using aPT-RS contained in the signal input from IDFT section 604, and corrects(performs CPE correction/ICI correction on) the input signal based onthe result of estimation as in reception apparatus 500 (CPE/ICIcorrector 505).

Note that, as in Embodiment 1, data EVM measurer 605 measures an EVM,using the signal input from IDFT section 604. Moreover, control-signalEVM determiner 608 measures an EVM, using the signal input from channelequalizer 603 as in Embodiment 1. More specifically, in Embodiment 2,data EVM measurer 605 assumes a point after the IDFT processing butbefore CPE/ICI correction in reception apparatus 500 (EVM measurementpoint) and measures an EVM. Moreover, control-signal EVM measurer 607assumes a point after the FFT processing and channel equalization inreception apparatus 500 (EVM measurement point) and measures an EVM.

Data EVM determiner 606 and control-signal EVM determiner 608 determinewhether or not CPE/ICI correction is present in reception apparatus 500and switch between the EVM requirement values (e.g., see FIG. 11) to beused in EVM determination, based on the result of determination.

Data EVM determiner 606 and control-signal EVM determiner 608, forexample, may check whether or not use of a PT-RS is indicated (i.e.,whether or not a PT-RS is contained in a signal from transmissionapparatus 400) and switch between the EVM requirement values to be usedin EVM determination, in accordance with the result of checking as inreception apparatus 500 (PT-RS checker 504). Alternatively, data EVMdeterminer 606 and control-signal EVM determiner 608 may switch betweenthe EVM requirement values to be used in EVM determination, inaccordance with a transmission parameter (such as frequency band ormodulation order) used for a signal transmitted from transmissionapparatus 400, as in Embodiment 1. Note that, information indicatingwhether or not a PT-RS is used or information on the frequency band orthe modulation order to be used for the signal may be indicatedexplicitly or implicitly using a control signal and/or the like.

Alternatively, in Embodiment 2, measurement apparatus 800 (measurementapparatus having a CPE/ICI correction feature) may perform EVMdetermination for transmission apparatus 400 that requires CPE/ICIcorrection, and measurement apparatus 600 (measurement apparatus havingno CPE/ICI correction feature) described in Embodiment 1 may perform EVMdetermination for transmission apparatus 400 that requires no CPE/ICIcorrection.

As described above, measurement apparatus 800 switches between EVMrequirement values to be used in EVM determination, in accordance withnecessity of CPE/ICI correction (whether or not CPE/ICI correction ispresent).

Accordingly, measurement apparatus 800 can appropriately evaluate an EVMmeasurement value according to whether or not CPE/ICI correction isconsidered necessary. More specifically, measurement apparatus 800 canperform EVM determination, taking into account the CPE/ICI correction(improvement of EVM) in reception apparatus 500 for transmissionapparatus 400 for which CPE/ICI correction is considered necessary. Morespecifically, measurement apparatus 800 can allow for communication fortransmission apparatus 400 having the phase noise not allowed under thecurrent test standard, using a test standard that takes into account theimprovement of an EVM by the CPE/ICI correction in reception apparatus500.

As described above, measurement-target transmission apparatus 400 forwhich the CPE/ICI correction is considered necessary can performcommunication using the modulation scheme with reception apparatus 500provided with a CPE/ICI correction feature, in a case where arequirement by the EVM requirement value (b) of the case where CPE/ICIcorrection is necessary illustrated in FIG. 11 is satisfied in EVMdetermination by measurement apparatus 800.

Moreover, measurement-target transmission apparatus 400 can use localoscillator 406 which produces a phase noise that may not be allowedunder the current test standard in the case where the CPE/ICI correctionis considered necessary. Stated differently, transmission apparatus 400does not have to include a high performance local oscillator forsuppressing production of the phase noise to an extent allowable underthe current test standard even in the case where the CPE/ICI correctionis considered necessary. Thus, an increase in configuration or costs oflocal oscillator 406 provided to transmission apparatus 400 can beprevented.

Operation Examples 1 and 2 of Embodiment 2 have been described thus far.

As described above, in Embodiment 2, as with the current test standardin measurement apparatuses 700 and 800, an EVM having no effect ofCPE/ICE correction (EVM before CPE/ICI correction) is measured while anEVM requirement value taking into account the CPE/ICI correction inreception apparatuses 200 and 500 (i.e., new test standard) isconfigured. In a case where CPE/ICI correction is determined to benecessary for a signal transmitted from transmission apparatuses 100 and400, measurement apparatuses 700 and 800 perform EVM determination fortransmission apparatuses 100 and 400 based on the new test standard,respectively.

Thus, according to Embodiment 2, measurement apparatuses 700 and 800 caneach appropriately determine an EVM measurement value, taking intoaccount the CPE/ICI correction.

Moreover, according to Embodiment 2, switching between the EVMrequirement values in measurement apparatuses 700 and 800 according towhether or not the CPE/ICI correction in reception apparatuses 200 and500 is necessary allows transmission apparatuses 100 and 400 (basestation or mobile station) to include a local oscillator producing aphase noise that may not be allowed under the current test standard.More specifically, transmission apparatuses 100 and 400 (base station ormobile station) do not have to include a high performance localoscillator to be allowed under the current test standard.

Furthermore, measurement apparatuses 700 and 800 determine whether ornot the new test standard is applied in EVM determination based onwhether or not the CPE/ICI correction is necessary in receptionapparatuses 200 and 500 for a signal transmitted from transmissionapparatuses 100 and 400. Thus, measurement apparatuses 700 and 800 caneach appropriately perform EVM determination in both cases where theCPE/ICI correction is necessary and where the CPE/ICI correction isunnecessary.

Embodiment 3

In Embodiments 1 and 2, the case has been described where a measurementapparatus measures an EVM having no effect of CPE/ICI correction (EVMbefore CPE/ICI correction) as in the current test standard. Meanwhile,in Embodiment 3, a case will be described where a measurement apparatusmeasures an EVM having the effect of CPE/ICI correction (EVM afterCPE/ICI correction).

Hereinafter, a description will be given of a configuration of acommunication system using a CP-OFDM scheme in Operation Example 1 and aconfiguration of a communication system using a DFT-S-OFDM scheme inOperation Example 2 in a manner similar to Embodiment 1.

OPERATION EXAMPLE 1

A transmission apparatus and a reception apparatus according toEmbodiment 3 include basic configurations common to transmissionapparatus 100 and reception apparatus 200 according to Embodiment 1, sothat a description will be given while FIGS. 3 and 4 are incorporatedherein.

[Configuration of Measurement Apparatus]

FIG. 14 is a block diagram illustrating a configuration of measurementapparatus 900 according to Operation Example 1 of Embodiment 3.Measurement apparatus 900 illustrated in FIG. 14 measures an EVM of ameasurement-target transmission apparatus that transmits a CP-OFDMsignal (e.g., transmission apparatus 100 illustrated in FIG. 3).

Note that, in FIG. 14, components that are similar to the components inEmbodiment 1 (FIG. 5) are assigned the same reference numerals and theirdescriptions are omitted. More specifically, measurement apparatus 900illustrated in FIG. 14 further includes CPE/ICI corrector 901 inaddition to the components that are similar to the components ofmeasurement apparatus 300 illustrated in FIG. 5.

CPE/ICI corrector 901 estimates the CPE/ICI of an input signal, using aPT-RS contained in the signal input from channel equalizer 304 andcorrects (performs CPE correction/ICI correction on) the input signalbased on the result of estimation as in reception apparatus 200 (CPE/ICIcorrector 205). CPE/ICI corrector 901 outputs the signal obtained afterthe CPE/ICI correction to EVM measurer 305.

EVM measurer 305 measures an EVM, using the signal input from CPE/ICIcorrector 901 (signal after CPE/ICI correction). More specifically, inEmbodiment 3, EVM measurer 305 assumes a point after FFT processing,channel equalization, and CPE/ICI correction in reception apparatus 200(EVM measurement point) and measures an EVM.

Note that, CPE/ICI corrector 901, for example, may check whether or notuse of a PT-RS is indicated (i.e., whether or not a PT-RS is containedin the signal from transmission apparatus 100) and determine whether ornot to perform CPE/ICI correction, in accordance with the result ofchecking as in reception apparatus 200 (PT-RS checker 204). Morespecifically, CPE/ICI corrector 901 outputs the signal input fromchannel equalizer 304 to EVM measurer 305 without performing CPE/ICIcorrection in a case where no PT-RS is used. Alternatively, CPE/ICIcorrector 901 may check whether or not to perform CPE/ICI correction inaccordance with a transmission parameter (such as frequency band ormodulation order) used for the signal transmitted from transmissionapparatus 100, as in Embodiment 1. Note that, information indicatingwhether or not a PT-RS is used or information on the frequency band ormodulation order to be used for the signal may be indicated explicitlyor implicitly using a control signal and/or the like.

EVM determiner 306 determines whether or not the EVM measurement valueinput from EVM measurer 305 satisfies a prescribed requirement (whetheror not the EVM measurement value is equal to or less than the EVMrequirement value).

FIG. 15 illustrates examples of EVM requirement values used in EVMdetermination by EVM determiner 306 according to Embodiment 3. The EVMrequirement values illustrated in FIG. 15 are identical to the EVMrequirement values (a) of the case where CPE/ICI correction isunnecessary illustrated in FIG. 6 as an example. Note that, the EVMrequirement values used in Embodiment 3 are not limited to be the sameas the EVM requirement values illustrated in FIG. 6.

As illustrated in FIG. 15, EVM determiner 306 performs EVM determinationusing the same EVM requirement value regardless of whether or notCPE/ICI correction is necessary. More specifically, in a case whereCPE/ICI correction is unnecessary, EVM determiner 306 determines whetheror not the EVM measurement value measured using the signal fromtransmission apparatus 100 is equal to or less than the EVM requirementvalue illustrated in FIG. 15 as with the current test standard.Meanwhile, in a case where CPE/ICI correction is necessary, EVMdeterminer 306 determines whether or not the EVM measurement valuemeasured using the signal obtained after the CPE/ICI correction isperformed on the signal from transmission apparatus 100 is equal to orless than the EVM requirement value illustrated in FIG. 15.

More specifically, in a case where CPE/ICI correction is necessary,measurement apparatus 900 can evaluate an EVM taking into account theCPE/ICI correction by performing EVM measurement using the signalobtained after the CPE/ICI correction. More specifically, measurementapparatus 900 improves the EVM as in reception apparatus 200 byperforming CPE/ICI correction in a case where CPE/ICI correction isnecessary, thereby performing EVM determination, using the same standard(the same EVM requirement value) as that of the case where CPE/ICIcorrection is unnecessary.

As described above, measurement apparatus 900 can perform CPE/ICIcorrection similar to that performed by reception apparatus 200, so thatmeasurement apparatus 900 can allow for communication under the currenttest standard even for transmission apparatus 100 having a phase noisenot allowed under the current test standard when CPE/ICI correction isnot taken into account.

In the manner described above, measurement-target transmission apparatus100 for which the CPE/ICI correction is considered necessary can performcommunication using the modulation scheme with reception apparatus 200provided with a CPE/ICI correction feature, in a case where arequirement by the EVM requirement value illustrated in FIG. 15 issatisfied in EVM determination by measurement apparatus 900.

In addition, measurement-target transmission apparatus 100 can use localoscillator 106 which produces a phase noise that may not be allowedunder the current test standard in a case where the CPE/ICI correctionis necessary. Stated differently, transmission apparatus 100 does nothave to include a high performance local oscillator for suppressingproduction of the phase noise to an extent allowable under the currenttest standard even in the case where the CPE/ICI correction isnecessary. Thus, an increase in configuration or costs of localoscillator 106 provided to transmission apparatus 100 can be prevented.

Note that, in Embodiment 3, measurement apparatus 900 (measurementapparatus having a CPE/ICI correction feature) may perform EVMmeasurement for transmission apparatus 100 that requires CPE/ICIcorrection, and measurement apparatus 300 (measurement apparatus havingno CPE/ICI correction feature) described in Embodiment 1 may perform EVMmeasurement for transmission apparatus 100 that requires no CPE/ICIcorrection. OPERATION EXAMPLE 2

A transmission apparatus and a reception apparatus according toEmbodiment 3 include basic configurations common to transmissionapparatus 400 and reception apparatus 500 according to Embodiment 1, sothat a description will be given while FIGS. 8 and 9 are incorporatedherein.

[Configuration of Measurement Apparatus]

FIG. 16 is a block diagram illustrating a configuration of measurementapparatus 1000 according to Operation Example 2 of Embodiment 3.Measurement apparatus 1000 illustrated in FIG. 16 measures an EVM of ameasurement-target transmission apparatus that transmits a DFT-S-OFDMsignal (e.g., transmission apparatus 400 illustrated in FIG. 8).

Note that, in FIG. 16, components that are similar to the components inEmbodiment 1 (FIG. 10) are assigned the same reference numerals andtheir descriptions are omitted. More specifically, measurement apparatus1000 illustrated in FIG. 16 further includes CPE/ICI corrector 1001 inaddition to the components that are similar to the components ofmeasurement apparatus 600 illustrated in FIG. 10.

CPE/ICI corrector 1001 estimates the CPE/ICI of an input signal, using aPT-RS contained in the signal input from channel equalizer 603, andcorrects (performs CPE correction/ICI correction on) the input signalbased on the result of estimation as in reception apparatus 500 (CPE/ICIcorrector 505). CPE/ICI corrector 1001 outputs the signal obtained afterthe CPE/ICI correction to IDFT section 604 and control-signal EVMmeasurer 607.

IDFT section 604 applies IDFT processing to the signal input fromCPE/ICI corrector 1001 (signal after CPE/ICI correction) and data EVMmeasurer 605 measures an EVM, using the signal obtained by the IDFTprocessing. Moreover, control-signal EVM measurer 607 measures an EVM,using the signal input from CPE/ICI corrector 1001 (signal after CPE/ICIcorrection). More specifically, in Embodiment 3, data EVM measurer 605assumes a point after the CPE/ICI correction and IDFT processing inreception apparatus 500 (EVM measurement point) and measures an EVM.Moreover, control-signal EVM measurer 607 assumes a point after FFTprocessing, channel equalization, and CPE/ICI correction in receptionapparatus 500 (EVM measurement point) and measures an EVM.

Note that, CPE/ICI corrector 1001 may check whether or not use of aPT-RS is indicated (i.e., whether or not a PT-RS is contained in thesignal from transmission apparatus 400) and determine whether or not toperform CPE/ICI correction in accordance with the result of checking asin reception apparatus 500 (PT-RS checker 504). More specifically,CPE/ICI corrector 1001 outputs the signal input from channel equalizer603 without performing CPE/ICI correction in a case where no PT-RS isused. Furthermore, CPE/ICI corrector 1001 may check whether or not toperform CPE/ICI correction in accordance with a transmission parameter(such as frequency band or modulation order) used for the signaltransmitted from transmission apparatus 400, as in Embodiment 1. Notethat, information indicating whether or not a PT-RS is used orinformation on the frequency band or the modulation order to be used forthe signal may be indicated explicitly or implicitly using a controlsignal and/or the like.

Data EVM determiner 606 and control-signal EVM determiner 608 determinewhether or not the EVM measurement values respectively input from dataEVM measurer 605 and control-signal EVM measurer 607 satisfy aprescribed requirement (whether or not the EVM measurement value isequal to or less than the EVM requirement value).

FIG. 17 illustrates examples of EVM requirement values used in EVMdetermination by data EVM determiner 606 and control-signal EVMdeterminer 608 according to Embodiment 3. The EVM requirement valuesillustrated in FIG. 17 are identical to the EVM requirement values (a)of the case where CPE/ICI correction is unnecessary illustrated in FIG.11 as an example. Note that, the EVM requirement values used inEmbodiment 3 are limited to be the same as the EVM requirement valuesillustrated in FIG. 11.

As illustrated in FIG. 17, data EVM determiner 606 and control-signalEVM determiner 608 perform EVM determination, using the same EVMrequirement value regardless of whether or not CPE/ICI correction isnecessary. More specifically, in a case where CPE/ICI correction isunnecessary, data EVM determiner 606 and control-signal EVM determiner608 determine whether or not the EVM measurement value measured usingthe signal from transmission apparatus 400 is equal to or less than theEVM requirement value illustrated in FIG. 17 as with the current teststandard. Meanwhile, in a case where CPE/ICI correction is necessary,data EVM determiner 606 and control-signal EVM determiner 608 determinewhether or not the EVM measurement value measured using the signalobtained after the CPE/ICI correction is performed on the signal fromtransmission apparatus 400 is equal to or less than the EVM requirementvalue illustrated in FIG. 17.

More specifically, in a case where CPE/ICI correction is necessary,measurement apparatus 1000 can evaluate an EVM taking into account theCPE/ICI correction by performing EVM measurement using the signalobtained after the CPE/ICI correction. In other words, measurementapparatus 1000 improves the EVM by performing CPE/ICI correction as inreception apparatus 500 in a case where CPE/ICI correction is necessary,thereby performing EVM determination using the same standard (the sameEVM requirement value) as that of the case where CPE/ICI correction isunnecessary.

As described above, measurement apparatus 1000 can perform CPE/ICIcorrection similar to that performed by reception apparatus 500, so thatmeasurement apparatus 1000 can allow for communication under the currenttest standard even for transmission apparatus 400 having a phase noisenot allowed under the current test standard when CPE/ICI correction isnot taken into account.

In the manner described above, measurement-target transmission apparatus400 for which the CPE/ICI correction is considered necessary can performcommunication using the modulation scheme with reception apparatus 500provided with a CPE/ICI correction feature in a case where a requirementby the EVM requirement value illustrated in FIG. 17 is satisfied in EVMdetermination by measurement apparatus 1000.

In addition, measurement-target transmission apparatus 400 can use localoscillator 406 which produces a phase noise that may not be allowedunder the current test standard in a case where the CPE/ICI correctionis necessary. Stated differently, transmission apparatus 400 does nothave to include a high performance local oscillator for suppressingproduction of the phase noise to an extent allowable under the currenttest standard even in the case where the CPE/ICI correction isnecessary. Thus, an increase in configuration or costs of localoscillator 406 provided to transmission apparatus 400 can be prevented.

Note that, in Embodiment 3, measurement apparatus 1000 (measurementapparatus having a CPE/ICI correction feature) may perform EVMmeasurement for transmission apparatus 100 that requires CPE/ICIcorrection, and measurement apparatus 600 (measurement apparatus havingno CPE/ICI correction feature) described in Embodiment 1 may perform EVMmeasurement for transmission apparatus 100 that requires no CPE/ICIcorrection.

Operation Examples 1 and 2 of Embodiment 3 have been described thus far.

As described above, in Embodiment 3, measurement apparatuses 900 and1000 measure an EVM having the effect of CPE/ICI correction (EVM afterCPE/ICI correction). Measurement apparatuses 900 and 1000 then perform,regardless of whether or not CPE/ICI correction is necessary for asignal transmitted from transmission apparatuses 100 and 400, EVMdetermination for transmission apparatuses 100 and 400 based on the sametest standard (e.g., similar to the current test standard).

Thus, according to Embodiment 3, measurement apparatuses 900 and 1000can appropriately determine an EVM measurement value, taking intoaccount the CPE/ICI correction.

Moreover, according to Embodiment 3, performing, in measurementapparatuses 900 and 1000, CPE/ICI correction in a case where CPE/ICIcorrection is necessary in reception apparatuses 200 and 500 allowstransmission apparatuses 100 and 400 (base station or mobile station) toinclude a local oscillator producing a phase noise that may not beallowed under the current test standard. More specifically, transmissionapparatuses 100 and 400 (base station or mobile station) do not have toinclude a high performance local oscillator to be allowed under thecurrent test standard.

Furthermore, measurement apparatuses 900 and 1000 determine whether ornot to perform CPE/ICI correction before EVM measurement, based onwhether or not CPE/ICI correction is necessary in reception apparatuses200 and 500 for a signal transmitted from transmission apparatuses 100and 400. Thus, measurement apparatuses 900 and 1000 can appropriatelyperform EVM determination in both cases where CPE/ICI correction isnecessary and where CPE/ICI correction is unnecessary.

Each embodiment of the present disclosure has been described thus far.

Note that, the term “CPE/ICI correction” used in the embodiments means“correcting a CPE” or “correcting ICI,” or “correcting both a CPE andICI.”

Moreover, in the embodiments described above, a phase noise may beproduced not only from a local oscillator of a transmission apparatusbut also from a local oscillator of a reception apparatus (notillustrated).

In addition, in the embodiments described above, channel equalizationrefers to processing that estimates a change in amplitude and/or phaseof a signal during spatial channel propagation between a transmissionapparatus and a reception apparatus, using a DMRS, and that corrects theamplitude and/or phase of the received signal based on the result ofestimation. The channel equalization does not include processing ofCPE/ICI correction using a PT-RS.

Furthermore, in the embodiments described above, the components ofantenna (not illustrated) ends are “CP removers 201 and 302” in theblock diagrams illustrating the configurations of measurementapparatuses 300, 700, and 900 for CP-OFDM, and reception apparatus 200(FIGS. 4, 5, 12, and 14). Meanwhile, the components of antenna (notillustrated) ends are “receivers 501 and 601” in the block diagramsillustrating the configurations of measurement apparatuses 600, 800, and1000 for DFT-S-OFDM, and reception apparatus 500 (FIGS. 9, 10, 13, and16). This is because the block diagrams are made to correspond to theblock diagrams described in the current test standard (e.g., see NPLs 3and 4), and not to make a point about uniqueness in these portions.Stated differently, the components of the reception antennas ends in themeasurement apparatuses and the reception apparatuses described in theabove embodiments are not limited to the components of the blockdiagrams mentioned above, and may include a component corresponding to acomponent of a transmission antenna end of a transmission apparatus. Thesame applies to the presence or absence of “time/frequency synchronizer301” in measurement apparatuses 300, 600, 700, 800, 900, and 1000.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware. Each functional block used in thedescription of each embodiment described above can be partly or entirelyrealized by an LSI such as an integrated circuit, and each processdescribed in each embodiment may be controlled partly or entirely by thesame LSI or a combination of LSIs. The LSI may be individually formed aschips, or one chip may be formed so as to include a part or all of thefunctional blocks. The LSI may include a data input and output coupledthereto. The LSI herein may be referred to as an IC, a system LSI, asuper LSI, or an ultra LSI depending on a difference in the degree ofintegration. However, the technique of implementing an integratedcircuit is not limited to the LSI and may be realized by using adedicated circuit, a general-purpose processor, or a special-purposeprocessor. In addition, a Field Programmable Gate Array (FPGA) that canbe programmed after the manufacture of the LSI or a reconfigurableprocessor in which the connections and the settings of circuit cellsdisposed inside the LSI can be reconfigured may be used. The presentdisclosure can be realized as digital processing or analogue processing.If future integrated circuit technology replaces LSIs as a result of theadvancement of semiconductor technology or other derivative technology,the functional blocks could be integrated using the future integratedcircuit technology. Biotechnology can also be applied.

A measurement apparatus of the present disclosure includes: measurementcircuitry, which, in operation, measures a modulation quality of asignal transmitted from a transmission apparatus; and determinationcircuitry, which, in operation, determines whether or not a measurementvalue of the modulation quality is equal to or less than a firstrequirement value, in a case where correction relating to a phase noiseof the transmission apparatus is necessary in a reception apparatus, thefirst requirement value being higher than a second requirement valueused in the determination of the measurement value in a case where thecorrection relating to the phase noise of the transmission apparatus isunnecessary in the reception apparatus.

In the measurement apparatus of the present disclosure, thedetermination circuitry determines whether or not the measurement valueis equal to or less than the first requirement value, in a case where afrequency band to which the signal is assigned is not less than athreshold, and determines whether or not the measurement value is equalto or less than the second requirement value, in a case where thefrequency band to which the signal is assigned is less than thethreshold.

In the measurement apparatus of the present disclosure, thedetermination circuitry determines whether or not the measurement valueis equal to or less than the first requirement value, in a case where amodulation order used for the signal is not less than a threshold, anddetermines whether or not the measurement value is equal to or less thanthe second requirement value, in a case where the modulation order usedfor the signal is less than the threshold.

In the measurement apparatus of the present disclosure, thedetermination circuitry determines whether or not the measurement valueis equal to or less than the first requirement value, in a case where aphase tracking reference signal is contained in the signal, anddetermines whether or not the measurement value is equal to or less thanthe second requirement value, in a case where the reference signal isnot contained in the signal.

A measurement apparatus of the present disclosure includes: correctioncircuitry, which, in operation, performs correction relating to a phasenoise for a signal transmitted from a transmission apparatus;measurement circuitry, which, in operation, measures a modulationquality of the signal after the correction relating to the phase noise;and determination circuitry, which, in operation, determines whether ornot a measurement value of the modulation quality is equal to or lessthan a requirement value.

A measurement method of the present disclosure includes: measuring amodulation quality of a signal transmitted from a transmissionapparatus; and determining whether or not a measurement value of themodulation quality is equal to or less than a first requirement value,in a case where correction relating to a phase noise of the transmissionapparatus is necessary in a reception apparatus, the first requirementvalue being higher than a second requirement value used in thedetermining of the measurement value in a case where the correctionrelating to the phase noise of the transmission apparatus is unnecessaryin the reception apparatus.

INDUSTRIAL APPLICABILITY

An aspect of this disclosure is useful in mobile communication systems.

REFERENCE SIGNS LIST

-   100, 400 Transmission apparatus-   101, 402 PT-RS generator-   102, 403 DMRS generator-   103, 404 Mapping section-   104, 405 IFFT section-   105 CP adder-   106, 406 Local oscillator-   107, 407 Frequency converter-   108, 408 Antenna-   200, 500 Reception apparatus-   201, 302 CP remover-   202, 303, 502, 602 FFT section-   203, 304, 503, 603 Channel equalizer-   204, 504 PT-RS checker-   205, 505, 701, 801, 901, 1001, CPE/ICI corrector-   206 Symbol detector-   300, 600, 700, 800, 900, 1000 Measurement apparatus-   301 Time/Frequency synchronizer-   305 EVM measurer-   306 EVM determiner-   401 DFT section-   501, 601 Receiver-   506, 604 IDFT section-   605 Data EVM measurer-   606 Data EVM determiner-   607 Control-signal EVM measurer-   608 Control-signal EVM determiner

1. A communication apparatus comprising: measurement circuitry, which,in operation, obtains a measurement value of a signal transmitted from atransmission apparatus; and determination circuitry, which, inoperation, compares the measurement value with a first requirement valuein a case where a phase tracking reference signal is contained in thesignal, and compares the measurement value with a second requirementvalue in a case where the phase tracking reference signal is notcontained in the signal, the first requirement value being higher thanthe second requirement value.
 2. A communication apparatus comprising:circuitry, which, in operation, generates a phase tracking referencesignal; and a transmitter, which, in operation, transmits a signal,wherein a first requirement value that is compared with a measurementvalue of the signal in a case where the phase tracking reference signalis contained in the signal is higher than a second requirement valuethat is compared with the measurement value of the signal in a casewhere the phase tracking reference signal is not contained in thesignal.
 3. A communication method comprising: obtaining a measurementvalue of a signal transmitted from a transmission apparatus; andcomparing the measurement value with a first requirement value in a casewhere a phase tracking reference signal is contained in the signal, andcomparing the measurement value with a second requirement value in acase where the phase tracking reference signal is not contained in thesignal, the first requirement value being higher than the secondrequirement value.
 4. A communication method comprising: generating aphase tracking reference signal; and transmitting a signal, wherein afirst requirement value that is compared with a measurement value of thesignal in a case where the phase tracking reference signal is containedin the signal is higher than a second requirement value that is comparedwith the measurement value of the signal in a case where the phasetracking reference signal is not contained in the signal.